Field of the Invention
This invention relates to a catalyst arrangement suitable for use in a tubular reactor in combination with a particulate catalyst, in particular with catalysts suitable for use in catalytic stream reforming processes.
Description of the Related Art
Tubular reactors in which reactants are passed through catalyst-filled tubes are well known and may be used for a variety of chemical processes. The tubes are conventionally filled with a particulate catalyst.
Structured catalysts on which the catalyst is supported or in which the particulate catalysts may be contained offer potential improvements in the performance of tubular reactors but difficulties in their use arise. We have devised a solution in which a structured catalyst is placed in the tubes above a particulate catalyst.
However, in use, a void may develop at the interface between the two catalysts, for example as a result of settling or shrinkage of the particulate catalyst in use. A void is undesirable as it can lead to over-heating or over-cooling of the tube wall in the vicinity of the void. Overheating in particular, as would be the case in catalytic steam reforming, is undesirable as it may lead to tube damage and a shortening of the life of the tube, the replacement of which is costly and undesirable.